Breast cancer is the most common cancer among Hispanic women in the United States (US). The incidence of breast cancer among Hispanics (83.5 per 100,000) is lower than that among non-Hispanic Whites (147.3 per 100,000); however, as Hispanic women adopt the practices of mainstream US culture, their risk for breast cancer increases. Further, Hispanic women are at increased risk for breast cancers with poor prognosis. The overarching theme of this PSO application is to understand and prevent pre-cursors of breast cancer and to reduce breast cancer morbidity and mortality among Latinas. This will be done at multiple levels and will engage researchers across several disciplines. Projects have been carefully designed to contribute understanding to and preventing breast cancer in Latinas. It is the lonq-term goal of this PSO application to understand the antecedents of breast cancer in the Latina population, to understand the types of breast cancer found in the Latina population, and develop and implement a comprehensive program of screening to increase the opportunities for early breast cancer detection among Latinas. Our short-term obiectives are to: 1. Increase breast cancer screening among age-eligible Latinas; 2. Understand the processes by which ancestry, BMI, inflammation, and breast cancer are related in Latinas 3. To understand aspects of the etiology of poor prognosis breast cancers by identifying risk factors related to triple negative (TN) and HER-2-overexpressing (H2E) tumors, which are more commonly found in Latinas compared to non-Hispanic whites 4. To understand the role of ancestry in breast cancer antecedents and incidence among Latinas. 5. To explore expression of genes involved in tumor-related pathways signaling. This application is committed to a comprehensive multi-level approach to reducing health disparities. Its projects range from the biologic and genetic to the social context within which people live. Through its four projects and cores, the proposed Center will cover a myriad of aspects of breast cancer, from biological processes and genetic pathways to individual determinants and social determinants of breast cancer.